Coral Reef 101: What are they and why are they important?

2016-06-20 12:15
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Hawaii — This week, more than 2 000 international reef scientists, policymakers and stakeholders are gathering in Hawaii to discuss what to do about the global decline of coral reefs. The International Coral Reef Symposium convened on Monday, 20 June, in Honolulu where attendees will try to create a more unified conservation plan for coral reefs.

After the most powerful El Nino on record heated the world's oceans to never-before-seen levels, huge swaths of once vibrant coral reefs that were teeming with life are now stark white ghost towns disintegrating into the sea.

And the world's top marine scientists are still struggling in the face of global warming and decades of devastating reef destruction to find the political and financial wherewithal to tackle the loss of these globally important ecosystems.

"What we have to do is to really translate the urgency," said Ruth Gates, president of the International Society for Reef Studies and director of the Hawaii Institute of Marine Biology.

Gates, who helped organise a conference this week said the scientific community needs to make it clear how "intimately reef health is intertwined with human health." She said researchers have to find a way to implement large scale solutions with the help of governments.

Consecutive years of coral bleaching have led to some of the most widespread mortality of reefs on record, leaving scientists in a race to save them. While bleached coral often recovers, multiple years weakens the organisms and increases the risk of death.

Mass bleaching has killed more than a third of the coral in the northern and central parts of Australia's Great Barrier Reef, though corals to the south have escaped with little damage, Traveller24 reported earlier this year. 

#ShockWildlifeTruths: One third of Great Barrier Reef coral killed by bleaching

In Thailand, island diving sites have also been closed to tourists due to bleaching damage recently. 

Researchers have achieved some success with projects such as creating coral nurseries and growing forms of "super coral" that can withstand harsher conditions. But much of that science is being done on a very small scale with limited funding.

Bob Richmond, director of the University of Hawaii's Kewalo Marine Laboratory, said the problems are very clear: "overfishing of reef herbivores and top predators, land-based sources of pollution and sedimentation, and the continued and growing impacts of climate change."

While reefs are major contributors to many coastal tourist economies, saving the world's coral isn't just about having pretty places for vacationers to explore. Reefs are integral to the overall ecosystem and are an essential component of everyday human existence.

Reefs not only provide habitat for most ocean fish consumed by humans, but they also shelter land from storm surges and rising sea levels. Coral has even been found to have medicinal properties.

Here's a look at what coral is, what role it plays in human life and what might happen if more of these important ecosystems are lost:

What are coral reefs?

Corals are animals related to jellyfish and anemones.

The organisms grow and form reefs in oceans around the world. Coral reefs support the most species of any marine environment, hosting countless kinds of fish, invertebrates and even mammals.

Coral reefs are comparable to rainforests in their biodiversity and importance to our overall ecosystem. According to the National Oceanic and Atmospheric Administration, there are over 800 species of coral that build reefs and hundreds of other soft and deep-sea coral species in the world.

Bleaching and Mortality 

When dramatic environmental changes occur, corals go through a process known as bleaching. Essentially, the corals become stressed, often from warmer water temperatures but also from things like pollution and acidification, and then release the symbiotic algae that they use for nutrition.

The loss of these symbionts leaves the coral white or pale colored, a sure sign the organism is stressed. If the bleaching is severe or recurs over consecutive years, the coral will likely die.

Some coral has shown resilience in warmer and more stressful conditions, and scientists are working to figure out why some do better than others.

Human uses 

Coral reefs are huge drivers for many coastal tourist economies, bringing in billions of dollars of revenue annually.

Many vacationers come to the tropics just to snorkel and dive on pristine reefs. But what many people don't know are the myriad of other ways humans benefit from coral reefs.

Reefs shelter land from storm surges and rising sea levels. Coral has even been found to have medicinal properties, including painkillers that are non-habit forming. Beyond that, coral reefs are home to the vast majority of fish that humans consume, and some island nations rely almost entirely on the reef for their daily sustenance. 

What is being done to help save the reefs? 

Researchers at the University of Hawaii's Institute of Marine Biology have been taking samples from corals that have shown tolerance for harsher conditions in Oahu's Kaneohe Bay and breeding them with other strong strains in slightly warmer than normal conditions to create a super coral.

The idea is make the corals more resilient by training them to adapt to tougher conditions before transplanting them into the ocean.

Another program run by the state of Hawaii has created seed banks and a fast-growing coral nursery for expediting coral restoration projects.

Most of Hawaii's species of coral are unlike other corals around the world in that they grow very slowly, which makes reef rebuilding in the state difficult. So officials came up with a plan to grow large chunks of coral in a fraction of the time it would normally take.

Coral reefs have almost always been studied up close, by scientists in the water looking at small portions of reefs.

But NASA's Jet Propulsion Laboratory is taking a wider view, from about seven kilometres above. NASA and other scientists recently launched a three-year campaign to gather new data on coral reefs worldwide. They are using specially designed imaging instruments attached to aircraft.

"The idea is to get a new perspective on coral reefs from above, to study them at a larger scale than we have been able to before, and then relate reef condition to the environment," said Bermuda Institute of Ocean Sciences' Eric Hochberg, principal investigator for the project.

What to read next on Traveller24

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